. Plant anatomy from the standpoint of the development and functions of the tissues, and handbook of micro-technic. phere. Water.—The photosynthetic cells are like all others in beingable to perform their functions better when in a state of tur-gidity. It is found, however, that isolated cells are able tophotosynthesize to a certain extent when in a flabby or evenplasmolyzed condition; and mosses and lichens are remarkablefor their power of photosynthesis even after they have begunto dry up. But the higher plants, with their waterproof epi-dermis, are unable to photosynthesize after the reduct
. Plant anatomy from the standpoint of the development and functions of the tissues, and handbook of micro-technic. phere. Water.—The photosynthetic cells are like all others in beingable to perform their functions better when in a state of tur-gidity. It is found, however, that isolated cells are able tophotosynthesize to a certain extent when in a flabby or evenplasmolyzed condition; and mosses and lichens are remarkablefor their power of photosynthesis even after they have begunto dry up. But the higher plants, with their waterproof epi-dermis, are unable to photosynthesize after the reduction inthe water content has caused the closure of the stomata, andthus prevented the continued inflow of carbon dioxide. Temperature.—The temperature may rise too high or falltoo low for photosynthesis; but, as might be anticipated, plantsin different latitudes are not affected alike by the same tem-peratures. For instance, in the tropics photosynthesis ceaseswhen the temperature becomes as low as 8° to 4° C., while inthe subtropics and temperate zones to produce a like result CONSTRUCTION OF PLANTS FOOD. the temperature must fall almost or quite to o° C.; and cool-temperate, arctic and alpine plants continue photosynthesizinguntil they become frozen. In regard to the maximum tem-perature, plants in general cease photosynthesizing after longexposure to approximately 38° C. Photosynthesis in the Lower Plants.—In the simplerAlgae where each individual consists of a single cell, a chain of cells forming a filament, ora thin lamina one cell thick,each cell contains one or morechloroplasts and carries onfood synthesis. In Pleuro-coccus the chloroplasts arelarge in comparison with thesize of the cell and seemnearly to fill the cell cavity. In(Edogonium and Nitella thechloroplasts are numerous andrelatively small. In Spirogyraeach cell* has one to few chloro-plasts each in the form of aspiral band (Fig. 82). Inthese as well as in the higherplants the chloroplasts lieembedded
Size: 1792px × 1394px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., boo, bookcentury1900, bookcollection, bookdecade1910, bookyear1910
